Overview

The 7Hz Salnotes Zero is an ultra-budget single-DD IEM that goes for a neutral-bright balance rather than the warmer tunings common at this price. It features a 10 mm dynamic driver with a metal-composite diaphragm, a detachable 0.78 mm 2-pin cable, and a stainless-steel faceplate[1]. Street price at Linsoul for the 3.5 mm, no-mic version is USD 22.99 (as of 2025-08-14)[1].

Scientific Validity

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• Frequency Response: Independent IEC60318-4/IEC711 measurements show an overall neutral-bright signature with elevated upper-mids/treble; the ~8 kHz bump is a coupler artefact and data above ~10 kHz should be treated cautiously[2].
• Distortion: Manufacturer spec lists THD < 1% @ 1 kHz[1], reasonable for this class.
• Drive Requirements: With 108 dB/V @ 1 kHz sensitivity and >32 Ω impedance[1], the SPL for a given voltage is:

  V_94dB = 10^((94-108)/20) ≈ 0.20 Vrms
  

  So ~102 dB at 0.5 Vrms and ~108 dB at 1 Vrms—well within the output of typical phones/DAC-dongles.

• Caveat: The FR peak around 5–6 kHz can sound spicy depending on tips and listener sensitivity[2].

Technology Level

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A competent, no-nonsense design: 10 mm DD with N52 magnet and metal-composite diaphragm, detachable 0.78 mm 2-pin, and a 4-core OFC cable (19×0.08 + 250D)[1]. Materials (steel faceplate + plastic shell) are solid for the price, though nothing here is groundbreaking.

Cost-Performance

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Among detachable-cable IEMs with comparable or better measured performance, the TANGZU Wan’er S.G is a key price anchor at USD 19.00 on Linsoul[3]. IEC711 measurements describe it as warm-neutral with a smoother treble balance[4].
Calculation: 19.00 ÷ 22.99 = 0.83.
Zero costs ~17% more than the cheapest equal-or-better option but remains highly competitive if you prefer a brighter, crisper presentation.

Reliability & Support

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Linsoul lists 1-year IEM and 3-month cable warranty[1]. Detachable cabling improves longevity versus fixed-cable sets. Accessories are basic; a carrying case is not included[1].

Rationality of Design Philosophy

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The goal—objectively-leaning neutrality at a rock-bottom price—is coherent and largely achieved. The trade-off is a potentially fatiguing treble peak for sensitive listeners; otherwise, the design prioritizes clarity and measurables in a cost-effective way.

Advice

• Great for listeners wanting clarity and a neutral-bright balance on a tight budget.
• If you prefer a smoother treble/warmer tilt, also consider TANGZU Wan’er S.G[3][4].
• Tip rolling (e.g., foam or thicker-bore silicone) can help tame the 5–6 kHz zing noted in measurements[2].

References

[1] Linsoul — 7HZ Salnotes Zero (official product page: specs, pricing, warranty)
https://www.linsoul.com/products/7hz-salnotes-zero

[2] Headphonesty — Review: 7Hz Salnotes Zero (IEC711 FR graph and notes)
https://www.headphonesty.com/2022/09/review-7hz-salnotes-zero/

[3] Linsoul — TANGZU Wan’er S.G (price/specs; detachable 2-pin)
https://www.linsoul.com/products/tangzu-waner-s-g

[4] Headphonesty — Review: Tangzu Wan’er (IEC711 FR; warm-neutral description)
https://www.headphonesty.com/2023/01/review-tangzu-waner/

(2025.8.14)